摘要:

Fourteen patients aged between 49 and 92 years who had suffered from one or more attacks of transient global amnesia (TGA) have been followed for a mean interval of 30 months. Thirteen patients had one or more risk factors for cerebrovascular disease, such as hypertension, cardiac abnormalities, diabetes and hyperlipidemia. Clinical evidence for vertebrobasilar arterial insufficiency was demonstrated in 11 cases. EEG examination revealed bitemporal or bioccipital slow wave activity. Four-vessel arteriography showed atherosclerotic, stenotic, or occlusive lesions predominantly in the vertebrobasilar and posterior cerebral arterial systems. Five patients without recurrence of TGA showed no permanent impairment of memory, whereas eight who had recurrent attacks of TGA showed permanent memory impairment as well as mild visual-spatial or visual-motor dyspraxia as judged by neuropsychological tests on follow-up visits. “Amnesic stroke” with permanent and gross memory defect and dyspraxia occurred in two patients.It is concluded that the majority of transient global amnesic episodes in the elderly or in those with the risk factors listed above result from cerebrovascular insufficiency particularly in the territory of vertebrobasilar and posterior cerebral arterial systems (which supply major portions of the ascending reticular activating system, parahippocampal-fornical-mamillary system, inferomedial aspects of the temporal lobe and occipital lobe). Repeated attacks of TGA are not rare and with each attack the likelihood increases of permanent memory deficits and progressive dementia. A rarer outcome is cerebral infarction in the territory of posterior cerebral arteries commonly referred to as “amnesic stroke.”

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

The severity of atherosclerotic involvement of intracranial cerebral arteries was assessed at autopsy in 3,315 adult subjects. Ponderal index values were calculated for each sex and ten-year age group. In most age groups, subjects with cerebral vascular disease, or one or more of several conditions known to be associated with increased cerebral atherosclerosis, had higher relative body weight than did subjects without those conditions. Subjects in the lower quartile of ponderal index distribution (“overweight” group) had more severe cerebral atherosclerosis than did subjects in the upper quartile (“underweight” group). However, when subjects with disease conditions known to be associated with increased cerebral atherosclerosis were excluded from the analysis, no relationship between relative body weight and severity of cerebral atherosclerosis could be demonstrated. Clinical and/or pathological evidence of cerebral vascular disease was apparently present more often in “overweight” than in “underweight” subjects, at least in certain age groups.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Patients with clinically unsuspected pituitary adenomas may present with sudden severe frontal headaches, stupor, ophthalmoplegia, meningeal irritation, compression of the optic nerves or chiasm, and abnormal cerebrospinal fluid. These findings are commonly misinterpreted as due to a ruptured cerebral aneurysm. The clinical features and controversial pathogenic mechanisms of pituitary apoplexy are reviewed. An unusual case of pituitary apoplexy with many atheromatous emboli in the tumor is presented. This previously undescribed possible cause of pituitary apoplexy should be considered in older patients with known predisposing factors for systemic atheromatous embolism.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Cerebral blood flow was measured with the133Xenon clearance method during short-lasting (20 minutes) and more prolonged (90 minutes) infusions of Na2CO3solutions in anesthetized cats under controlled ventilation. The infusion protocol was regulated so as to produce a given increase in the plasma [HCO3−] in the first 15 minutes, followed by a constant high plasma level for the rest of the infusion period. A high Paco3level was induced before and at the end of the infusion, when prolonged infusions were made. The results indicate that, in acute experiments (20 minutes), an increase in plasma [HCO3−] of 14 mEq/l does not influence CBF. During more prolonged infusions (90 minutes), an increase of 12 mEq/l produces a reduction of CBF and an increase in the CSF [HCO3−]. These changes are more pronounced when the increase in plasma [HCO3−] is more marked (18 mEq/l).

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Determinations of whole blood viscosity by means of a cone plate viscometer at 37°C and at shear rates of 212, 42, 21 and 11 sec−1were done in 50 patients with recent cerebral infarction of the carotid system, and the values compared to a control group of 50 patients of the same age. In stroke patients a statistically significant elevation of blood viscosity over the whole range of shear rates was demonstrated, more obviously significant at low shear rates (P < 0.0001) such as occur in small vessels. Since the mean hematocrit levels of both groups were in the normal range, it was considered that hematocrit values estimated from peripheral blood do not necessarily give accurate information about viscosity levels existing at the same time.In cases of severe cerebral infarction without angiographically demonstrable stenotic or obstructive lesions, it was suggested that high blood viscosity impairs hemodynamic conditions in the cerebral microvasculature in addition to narrow arteriosclerotic vessels, changes in flow velocity gradients and insufficient collateral circulation.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Due to certain anthropomorphic features of the cerebral circulation, monkeys are generally preferable to lower species in experimental models of stroke. By injecting specially molded silicone cylinders through internal carotid artery cannulas, segmental occlusions of the middle cerebral artery were produced in macaques. This embolic method produced cerebral infarction in all instances while the integrity of skull and intracranial collateral circulation were preserved. Because only neck surgery was required, local anesthesia could be used, permitting observation of acute infarctions in sedated, conscious animals.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Carotid endarterectomy was performed on 73 occasions using the following regimen during the operative period: (1) general anesthesia with normothermia, (2) maintaining a normal or slightly elevated arterial oxygen tension (Pao2, (3) maintaining a normal or low arterial carbon dioxide tension (Pco2), (4) maintaining systemic arterial pressure (SAP) at normal or slightly elevated levels, (5) employing a bypass shunt in all cases, and (6) utilizing transient systemic anticoagulation with heparin. The rationale for this regimen is explained in terms of current concepts of cerebral blood flow and metabolism. No new neurological deficit has appeared after operation using these techniques.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Dogs breathed one of four gas mixtures (5% CO2-95% O2, 5% CO2-95% air, 10% CO2-90% O2, and 10% CO2-90% air) for as long as two hours. Regional cerebral blood flow as well as flow in nasal, otic, pituitary and skin tissue were measured by means of 15 ± 5 μ radioactively labeled microspheres. The normal values for cerebral blood flow and arterial blood gases were very similar to those of other investigators. Inhalation of CO2induced an increase in cerebral blood flow that was significantly higher than is usually reported. Increases varied from 100% (with 5% CO2-95% air) to 250% (with 10% CO2-90% O2). Blood flow in the temporal bone behaved much like that of brain in response to CO2. In most instances, the pituitary gland blood flow did not increase with inhalation of CO2.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

Blood coagulability in patients following cerebral infarction was studied utilizing the thromboelastograph (TEG). Cerebral infarction patients from two separate institutions were studied within 24 to 48 hours after onset of stroke. Ninety-four stroke patients from one institution and 109 from another yielded a total stroke population of 203 patients for this study. Fifty-nine age-matched normals were used as a control group. Frequency distribution curves were determined for a TEG ratio of ma/(r + k). The 59 controls exhibited a normal frequency distribution between the values of 1.6 and 4.0. Both groups of stroke patients revealed an increased number of patients with a ratio exceeding 4.0, suggesting a hypercoagulable state exists following cerebral infarction in approximately 29% to 38% of the patients studied.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID

摘要:

The effect of middle cerebral arterial occlusion on blood flow over the parietal aspect of the cortex and in the putamen of baboons has been assessed by the technique of hydrogen clearance. Reduction of blood flow was present over the entire lateral aspect of the cerebral hemisphere, maximal in the regions of frontal, parietal and temporal opercula where the blood flow was reduced to some 25% of control levels, and in the deep nuclei where the average flow in three animals was 20%. Reactivity to carbon dioxide was correspondingly reduced and, indeed, paradoxical reactivity or intracerebral steal was found in the most densely ischemic opercular zone. There was no evidence in the present studies of any area with increased tissue blood flow following middle cerebral occlusion.Under control conditions, some inhomogeneity of blood flow was evident in the cortical areas studied, the parietal association areas having a significantly lower blood flow than the more anterior regions of the hemisphere.

ISSN:0039-2499    

出版商:OVID    

年代:1974

数据来源: OVID